Failure of the natural gas pipeline can have severe consequences to individuals, economy, environment and the public in term of consequential damage and property losses. There are various causes of natural gas pipeline failures among which third-party damage offers a high contribution. To minimize third-party damage of NGP contributing factors should be studied to establish viable solutions for risk mitigation. In this paper, factors contributing to third-party damage of NPG in Dar es Salaam region have been studied. A fault tree was constructed and by utilizing fuzzy logic and expert elicitation, the failure probabilities of the basic event were established. The prioritization of factors was performed by criticality measures. The results showed that lack of regulations awareness, unplanned settlements, encroachment and lack of HSE knowledge are among the high contributors of Third-party damage. Therefore, addressing these factors will help to mitigate NGP failures by third party damage.
With the increase of residential energy consumption, its proportion in primary energy consumption is higher and higher. Accurate prediction of residential electricity consumption is the premise of rational residential energy management. In this paper, a novel multi-step prediction model using particle swarm optimization (PSO), Holt-Winter (HW) method, and extreme learning machine (ELM) network is proposed for forecasting household power consumption. The HW model optimized by PSO is the main predictor and used to deal with the periodicity and seasonality of household electricity load. ELM model is introduced as the correction predictor to predict the prediction error of HW, so as to improve the prediction accuracy. The experimental results show that the PSO-HW-ELM model has higher prediction accuracy and better stability compared with the single HW and ELM model.
The purpose of this study is to understand the effect of an over-estimated cooling set-point temperature (28°C) on work productivity in Korea’s public buildings during the summer season. Two experiments were conducted. The first experiment aimed at measuring work performance through typing and cognitive tests and detecting work stress using an electroencephalogram at 28°C. The second experiment was conducted at 24°C with the same contents as the first. The results showed that a cooling set-point temperature of “28°C” brings benefits in terms of energy consumption, but it drops work performance, thereby having an adverse effect on overall productivity.
This paper presents a power management strategy to control a DC microgrid considering the operation in the grid connected mode. The analyzed system is composed of the utility grid interfaced with a voltage source converter, an energy storage system (ESS), a distributed generator and the customer loads. The proposed power management is considered as a master-slave technique, in which the VSC operates as a master grid-forming converter, while the ESS is a slave grid- supporting unity and the distributed generator works as a grid-feeding unity tracking the maximum power point. This management strategy is presented in details and its impact over the DC link voltage, the power flow and the ESS state of charge is analyzed. MATLAB/Simulink simulations are performed to obtain the results. The obtained results show that the proposed strategy is reliable and leads to better controllability over the power flow in the DC microgrid when compared with the hierarchical control.
Static synchronous compensator (STATCOM) can effectively improve the power quality in the mediumvoltage distributed energy system (DES). In order to keep the system stable operation, fault-tolerant ability should be maintained to improve the reliability of STATCOM. With the idea of virtual capacitor voltage, a simplified fault-tolerant control scheme is proposed for popular cascaded H-bridge (CHB) based STATCOM. First, an improved modulation method is adopted to significantly reduce these carrier waves. Then, based on the virtual capacitor voltage, the control scheme during the cell fault can be further simplified. Finally, the detailed postfault operation principle is presented according to different operation conditions of STATCOM, where the capacitor voltages in the faulty phase can remain unchanged in certain cases. Validation results verify the effectiveness of the proposed fault-tolerant scheme.
This paper presented a torque distribution strategy based on linear time-varying quadratic programming (LTV-QP) for yaw stability control of all-wheelindependent- drive electric vehicles. A two-degree-offreedom vehicle dynamic model was established to figure out the desired vehicle states including sideslip angle of the centroid of vehicle and the yaw moment, which was used as the reference signal of the LTV-QP controller. However, the influence of the time-varying steering angle was generally not taken into account. A QP-based torque distribution strategy is put forward to reduce the yaw rate error caused by them. The proposed strategy is evaluated in Matlab/Simulink to track the reference yaw moment and optimize the torque distribution. The results indicate that the LTV-QP controller can effectively distribute the torques of four in-wheel motors and significantly improve the vehicle yaw stability.
A 2D filter is proposed for battery incremental capacity curve filtering in a cyclic aging test. The filter works in two directions, namely, from time to time and from batch (cycle) to batch. In details, a simple low-pass filter is applied in the batch direction, and a bias-corrected Gaussian filter is applied in the time direction. Experimental results show that the root-meansquare-error of the proposed method is 20% lower than the neural-network-based benchmarking algorithm. Over-fitting and under-fitting could also be resolved.
Building & transportation have been the major sectors for the energy consumption of modern city. The recent development of distributed energy resources is attracting extensive attention from city designers, primarily driven by the transition need towards a future smart city. Key challenges exist from planning, design, construction, build, operation and service due to the barrier in regulation and engineering practice between building, transportation and energy industry as well information technology & recent rising industry of the Internet of things (IoT). This paper proposed a novel energy system infrastructure to create a synergy to accommodate the diverse temporal and spatial features cross building, transportation, energy and information domain. In addition, this concept is carrying out in an official area for 2022 Beijing Winter Olympic game and is also discussing for the implement in NEOM, Saudi Arabia. This paper mainly discusses the latest progress of the demonstration for the 2022 Winter Olympic.
Industrial parks have shown an important development trend of employing distributed generations instead of traditional centralized power supply. This paper studies the planning method of power supply systems in industrial parks, considering demand side response based on day‐ahead real time pricing. An improved demand side response model is proposed to solve the imbalance of energy shifting and overwork of demand side response when price elasticity matrix is used. Furthermore, an optimal planning model is established, taking minimum total cost as the optimization objective, and solved by the GA‐PS algorithm. Additionally, two indexes, the ratio of distributed generation deficiency energy and the ratio of distributed generation deficiency hours, are proposed to characterize the complementary of multi‐energy. Finally, a case of a typical power supply system in an industrial park is given to validate the proposed method.
The reliability evaluation of distribution network is an important part of power system. In the extreme situation caused by aging or weather, the multi-fault affect the distribution network reliability. There are only few reliability assessment approach considered the impact of multi-faults. It’s necessary to have a method that can ensure both accuracy and efficiency. The impact increment method based on Monte Carlo sampling (IIMC) can meet the requirements in transmission network. After improving the independent faults identification by distribution network structure, the RBTS Bus6 system is used as an example to test the effectiveness of IIMC. Compared with traditional Monte Carlo sampling. When the failure rate of components is high for the aging and other reasons, the result can show the advantage of IIMC.